Diaphragm apparatus for x-ray tubes



May 16, 1933. 1.. RAAB DIAPHRAGM APPARATUS FOR X-RAY TUBES Filed May 28, 1929 INVENTOR zeammeo EAAB A TTOE/VEYS Patented May 16, 1933 UNITED. STATES PATENT OFFICE LEONHARD RAA B, OF ERLANGEN, GERMANY DIAI' HRAGH APPARATUS FOR X-RAY TUBES Application filed Kay 28, 1929, Serial No. 366,569, and in Germany 11121129, 1828.

- ing at a short distance from the point of emission of the X-rays, the outline of the image of the aperture formed by said diaphragms manifests considerable indistinctness even at arelatively short distance therefrom. Owing tothe importance of avoiding an excessive increase in the size of the diaphragm apparatus, as well as the avoidance of unusual electrical effects between the electrode caps of the X-ray tube and the diaphragms, when the latter are open, it has been hitherto impossible to remedy the indistinctness of, the image by arranging the diaphragms ata greater distance from said tube.

According to the present invention, the

above drawbacks are overcome by the provision of a, diaphragm apparatus wherein the adjustable diaphragms of at least one pair are disposed in spaced relation to each other. v i

The inventive idea involved is capable of receiving a variety of mechanical expres sions, some of which, for purposes of illus tration, are shown in the accompanying drawing wherein Figure 1 is a'vertical section of one form of diaphragm apparatus, showing it attaiahed to the protective casing of an X-ray tu e;

Figure 2 is a front elevation of the apparatus with the front wall of the casing therefor removed; and V Figure 3 is a view similar to Figure 1, illustrating another form of the invention.

Referring more particularlyto the accomgo 'panying drawing, 1 indicates the protective casing of the X-ray tube b secured to the latter in the usual manner.

The diaphragm apparatus shown in Figures land 2 comprises a casing 0 of rectangular formation and made of a substance which is practically impermeable to X-rays, said casing being secured directly to the casing a and having an inner or rear aperture d in the base e through which the pencil of '00 X-rays emanates from the tube b.

In the interior of the casing 0 adjacent the vertical side walls thereof there are provided on the base e two pairs of pivots f and g, only one pivot of each pair being shown inasmuch 6 V as Figure 1 is a sectional view and does not show the second side wall.

A similar pair of pivots h, perpendicular to the pivots f, g, is disposed in the top and bottom of the casing 0 adjacent the verticalm side Wall shown and a fourth pair of pivots (not shown in Figure 1) similar to the pivots h are provided near the vertical side wall of the casing 0 whichis opposite the one illustrated. I

Mounted on the upper pair of pivots f for pivotal movement in a vertical plane is a diaphragm actuating element 2' and a similarly supported actuating element is carried by the lower pair of pivots g. The pivots h, 30 shown in Figure 1, carry an actuating element m which moves in a horizontal plane and a fourth element (not shown) is supported like the element m by the other pair of pivots similar to said pivots h. All four of the diaphragm actuating elements are of the same construction (see element and may be described as fork-like members having arms at the ends thereof. Thus the elements i, 72, respectively, have two arms 0 and p (one from the X-ray tube.

shown in each instance) and the element m has the arms Q and r at its opposite ends; the fourth element, similar to am, being likewise constructed. In order that the two elementsz' and 76 may be simultaneously adjusted toward and away from each other, they are connected by at least one pair of links or having a common pivotal. point 7 which may be actuated in any preferred manner. Likewise, the other pair of elements, including in, may be similarly adjusted by links (not shown).

lVithin the casing 0 and designed to be actuated'by the elements 11, 7a, et cetera, are four sets of diaphragms If, a, 'v and z, the first two sets being arrangedhorizontally and the last two vertically. These various sets combine to form a number oil groups, each con.- sisting of four diaphragms t, u, '0, 2 and, as best shown in Figure 1, the various groups are spaced apart and are different distances The ends of the different diaphragms are preferably made to slide in guide grooves in the walls of the casing 0 in planes perpendicular to the direction oi the X-rays, only the grooves w, a: for the diaphragms '1) being illustrated for the sake of clearness. The arms 9 of the actuating element 74 extend through openings 8 adjacent the ends oi the lower horizontal set of diaphragms a and, similarly, the arms of the other actuating elements of the apparatus pass through openings lll the diaphragms with which said elements are associated.

When the apparatus is in its open position the diaphragms are arranged as shown in full lines in Figure 1,the distance between parallel diaphragms of each group increasing from the X-ray tube outwardly. By adjusting the various links a, said diaphragms may be moved in the various guide grooves to the dotted line position of Figure 1, or to any intermediate stage, thereby regulating the size of the aperture tl'irough-which the pencil of X-rays will pass.

pencil of X-rays issuing from the point of" emission of the X-ray tube, at least one additional ad1ustable diaphragm is disposed in such a way that it will prevent, in. any of its positions, the escape of the X-rays, parl-l tl t"" tltl t" f"' blcll a1 3 it s em 1a s, 1a to no issue 1on1 the point of emlssion of the Xray tube.

mediate diaphragm, or of these intermediate dlaphragms, as the case may be, is efi'ected in In 7 this connection, the adjustment of this interan advantageous manner by means of the adjustment members, such as levers or the like.

Thus, in the diaphragm casing c (Figure 3) having the diaphragm aperture d in its base 0 which is attached to the X-ray tube (together with the anticathodo 1), there is arranged, in addition to the adjustable diaphragn'is t and a which limit the pencil of X- rays issuing from the point of emission 2, the intermediate pair of diaphragms l, 5 which serve for prevention of the escape of the X- rays (stem rays) that do not issue from the point of emission 2, but which may be emitted from a point 3 of the anticathode 1. The adjustment of the intermediate diaphragm is oxpediently effected by the levers 10, 11 which are connected with one another by means of a suitable system of links or levers 6, 7, 8 and which also serve for adjustment of the diaphragms t, u in a manner similar to that described in connection with Figure 2. The levers 10. 11 are constructed as twoarmed levers, the points of rotation f, g of which are situated. within the space between the diaphragms t, a which serve to limit the pencil of X- *ays issuing from the point of emission. 2.

The mechanism shown in Figure 3 operates as follows: Upon rotation of one of the levers 10 or 11 about its fixed pivot f or g from the position shown in Fig. 3 in an outward direction. the diaphragms u are moved away from each other so that the lower diaphragnl opening is enlarged. The transmission of the movement from one of the levers to theother occurs automatically through the connections 6, 7, 8, wherein the lever 6 is rigidly connected with the lever '10 at the iulcrum. The lever or arm 8 is rigidly connected with the lever 11 at the fulcrum 7, so

that upon clockwise swinging of the lower end of the lever 10, the lever (5 is similarly moved and through the linkage 7, 8 produces (-ouliter-clockwise oscillation of the lever 11. Similar movement of lever 11 produces a corresponding movement of lever 10. hen the lower ends of the levers 10 and 11, as viewed in Fig. 3, move outwardly, the upper ends thereof move inwardly. To the upper ends of the levers 10 and 11 are connected hook-like members each of which is connected to the op positely positioned diaphragm t; thus the lever 10 is connected with the right hand diaphragm t, while the lever ll is connected with the left hand diaphragm 6. Consequently, enlargement of the opening of the (lower) diaphragm u is accompanied by an enlarge ment of the opening of the (upper) diaphragm t.

The relative sizes of the openings of the upper and lower diaphragms can be adjusted by suitably selecting the ratio of the lengths of the parts of the lovers 10, 11, from their fulcra to the lower diaphragm u and to the, In similar fashion the hook-like members.

intermediate diaphragms 4, 5, through which the lower parts of the levers l and 11 pass can be so arranged and proportioned that they are carried along by the levers and 11 in such a manner that each such diaphragm in every position thereof intercepts those rays which emanate from points on the anticathode other than the point 2.

Vhat is claimed is:

1. A diaphragm mechanism for Xray tubes, comprising a'plurality of spaced diaphragm sets, each composed of a plurality of movable diaphragms consisting of strips of ray impervious material and forming a closed able outside of the pencil of useful rays and operative to intercept the stem rays, said operating mechanism being associated also with said intermediate diaphragm set to adjust the same and comprising a plurality of fork-like levers pivoted within said housin adjacent to the walls thereof, pairs of sai levers being linked together for conjoint operation.

In testimony whereof, I have affixed my signature.

LEONHARD RAAB.

figure, a housing for said diaphragm sets,

lation of said levers the diaphragms of the diaphragm sets are caused to move in planes perpendicular to the main direction of the rays.

3. A diaphragm mechanism as set forth in claim 1, including an intermediate diaphragm set arranged between the first-mentioned diaphragm sets and composed of a:

plurality of adjustable diaphragms positionable outside of the pencil of useful rays and operative to intercept the stem rays.

4. A diaphragm mechanism as set forth in claim 1, wherein each of said diaphragm sets is composed of four movable diaphragms, said operating mechanism comprising levers pivoted between the outermost and innermost diaphragn'i sets and passing through openings in said corresponding diaphragms ofthe diaphragm sets to adjust the same on movement of such levers.

5. A diaphragm mechanism as set forth in claim 1, including an intermediate diaphragm set arranged between the first-mentioned. diaphragm sets and composed of a plurality of adjustable diaphragms positionable outside of the pencil of useful rays and operative to intercept the stem rays, said operating mechanism being associated also with said intermediate diaphragm set to adjust the same.

6. A diaphragm mechanism as set forth in claim 1, including, an intermediate diaphragm set arranged between the first-mentioned diaphragm sets and composed of a plurality of adjustable diaphragms position- 

